CN114019915A - Multi-mobile-robot cooperative motion control system and control method thereof - Google Patents
Multi-mobile-robot cooperative motion control system and control method thereof Download PDFInfo
- Publication number
- CN114019915A CN114019915A CN202111297352.4A CN202111297352A CN114019915A CN 114019915 A CN114019915 A CN 114019915A CN 202111297352 A CN202111297352 A CN 202111297352A CN 114019915 A CN114019915 A CN 114019915A
- Authority
- CN
- China
- Prior art keywords
- unit
- motion
- unit module
- actuator
- wheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000000034 method Methods 0.000 title claims abstract description 39
- 238000005259 measurement Methods 0.000 claims abstract description 14
- 230000007246 mechanism Effects 0.000 claims description 7
- 238000003032 molecular docking Methods 0.000 claims description 7
- 230000008569 process Effects 0.000 claims description 7
- 230000001133 acceleration Effects 0.000 claims description 6
- 238000004891 communication Methods 0.000 claims description 6
- 239000011159 matrix material Substances 0.000 claims description 6
- 238000010606 normalization Methods 0.000 claims description 6
- 238000012545 processing Methods 0.000 claims description 6
- 230000009471 action Effects 0.000 claims description 5
- 230000008859 change Effects 0.000 claims description 4
- 230000006399 behavior Effects 0.000 claims description 3
- 230000005484 gravity Effects 0.000 claims description 3
- 238000011160 research Methods 0.000 description 6
- 230000036544 posture Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- 238000009795 derivation Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 210000001503 joint Anatomy 0.000 description 1
- 230000004044 response Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/416—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control of velocity, acceleration or deceleration
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/32—Operator till task planning
- G05B2219/32063—Adapt speed of tool as function of deviation from target rate of workpieces
Landscapes
- Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Manipulator (AREA)
Abstract
A multi-mobile robot cooperative motion control system and a control method thereof are disclosed, the system comprises an upper computer, an industrial personal computer, a driver, an inertia measurement unit and an encoder, wherein the upper computer is communicated with the industrial personal computer of each unit module, a wheel part actuator is connected with the driver and then connected with the industrial personal computer, the encoder is fixed at the actuator, and the inertia measurement unit is arranged at the mass center part of the unit module; the method comprises the steps of feeding back the current state of each unit module, constructing a discretized combination kinematic model and a weighted norm of an input variable, converting constraint conditions into a convex quadratic programming problem, solving the optimal solution of the current system input state, and finally inputting a required corner and speed to a wheel actuator to realize cooperative motion on the basis of realizing the local optimal solution. The invention enhances the synchronism and robustness of the cooperative motion of the multi-unit module, can realize the cooperative motion among a plurality of mobile unit modules and has higher fault tolerance.
Description
Technical Field
The invention relates to a distributed control system and a coordinated motion control method for a modular multi-mobile robot, and belongs to the technical field of multi-mobile robot control.
Background
The modular multi-mobile robot is characterized in that a single mobile robot is used as a unit module, and the unit modules with the same configuration or different configurations are combined according to a certain arrangement mode according to the requirements of a new working environment so as to meet the requirements of tasks. In the field of research of modular multi-mobile robots, whether a mobile robot has stronger motion capability and higher efficiency is directly related to the modular cooperative motion capability and the response speed. Among them, the high synchronism of cooperative motion and the low time delay of communication are the key points to guarantee the problem. In the process of cooperative motion, actions such as posture adjustment of each unit module and state adjustment of the whole combined module need to be realized, so that the cooperative motion is a challenging research direction in the research field of the cooperative motion of the mobile robot.
Aiming at the requirements of severe field operation such as unstructured terrain, soft ground and the like, the mobile robot is required to have strong obstacle crossing capability and strong robustness. Since it is difficult for a single wheeled mobile robot to satisfy the above requirements due to structural and capacity limitations, a concept of cooperative motion of a plurality of wheeled mobile robots has been proposed. And aiming at different task requirements, multiple mobile robots can be combined according to a specific mode to form a combined body structure with different structures, so that the mobile robot can adapt to different field working environments, and the adaptability of the whole system is enhanced. Meanwhile, high-difficulty actions can be completed among the multiple mobile robots in a coordinated mode, so that the performance requirement on a single module can be reduced, and the cost of the system can be greatly reduced.
Although the unit modules can be connected through the docking mechanism when being docked to form the combined module to move, the adjustment effect of the docking mechanism is limited, if the postures of the unit modules are only adjusted through the docking mechanism, the movement of the combined module tends to be in a divergent state along with the operation of the system, and therefore it is very important to design a high-synchronism cooperative motion control method. The human significance for researching strong robustness and efficiently realizing the wheel type mover is achieved by constructing a proper motion method and a motion planning mode: the high efficiency requires that the modules have mutually cooperative motion methods, so that the motion methods of the modules have high consistency; after the single wheeled mobile robot is modularized, unit modules with different configurations and movement capabilities can be selected according to different subtasks realized by the single wheeled mobile robot, so that the fault-tolerant capability of the whole system is improved, and the cost is reduced; aiming at the disturbance caused by terrain change or external force, the designed unit module has a reliable control method and is provided with a corresponding sensor to feed back the state information, so that the strong robustness of movement is realized.
For the research on the cooperative motion control of the multi-wheeled robot at present, the following problems also exist:
1) at present, most of multi-robot collaborative research aims at static tasks, only a model is initially established for static tasks and allocation under unknown complex environments, optimal benefits are not considered when most of research allocates and optimizes dynamic tasks, and individual and overall optimal energy consumption is rarely involved.
2) Due to the fact that the distributed control system lacks global clock performance, the robots can be out of synchronization when executing respective tasks, and overall system efficiency is reduced.
Disclosure of Invention
Aiming at the problems of the existing multi-wheel robot control technology, the invention provides a multi-mobile robot cooperative motion control system with low energy consumption and high efficiency, and also provides a control method of the system.
The invention discloses a multi-mobile-robot cooperative motion control system, which adopts the following technical scheme:
the multi-mobile robot comprises a plurality of unit modules with the same configuration or different configurations, wherein the unit modules are connected together through a docking mechanism, each unit module is provided with four wheel part actuators which independently turn and independently move, and a triangular or square combination body is formed according to different required tasks;
the control system comprises an upper computer, an industrial personal computer, drivers, inertia measurement units and encoders, wherein each unit module is provided with a corresponding industrial personal computer, a corresponding driver, an inertia measurement unit and a corresponding encoder, the upper computer is communicated with the industrial personal computers of the unit modules through a network communication protocol, a wheel part actuator is connected with the drivers and then connected with the industrial personal computers, the encoders are fixed at driving motors in the actuators, and the Inertia Measurement Units (IMUs) are arranged at mass center positions of the unit modules.
The encoder is used for detecting the rotation angle of a driving motor in the wheel part actuator, the advancing speed of the current wheel part actuator is obtained through the detected pulse number, the current advancing speed is compared with the preset advancing speed given quantity by the industrial personal computer, the pulse speed required to rotate by the driving motor is obtained, the industrial personal computer sends a processed instruction to the driver, and the driver continuously changes the rotating speed of the driving motor, so that each unit module and other unit modules are in the same stable motion state, and the cooperative motion is completed.
The inertia measurement unit sends the measured pose information of the unit modules to the industrial personal computer, a weighted norm is constructed by utilizing the pose information of the unit modules and the established model, the weighted norm is converted into an optimized convex quadratic programming problem through boundary constraint, the self movement error or the influence of external interference is reduced, the change of the pose of the unit modules is realized, and the cooperative motion is carried out in a better way by matching with other unit modules.
The control method of the system comprises the following steps: establishing a dynamic task model, a state feedback and a geometric method of cooperative motion; when the motion is needed, the current state and pose information of each unit module are fed back through an encoder and an inertia measurement unit, a discretized kinematic model of the combination and a weighted norm of an input variable are constructed, the weighted norm is converted into a convex quadratic programming problem by utilizing constraint conditions, and a required corner and speed are input to a wheel actuator to realize cooperative motion on the basis of realizing a local optimal solution by solving the optimal solution of the current input state; the method specifically comprises the following steps:
(1) the upper computer sends instructions and clock timestamps to the industrial personal computers of all the unit modules;
(2) the industrial personal computer receives and processes the command, compares the command with a clock of the industrial personal computer by using the timestamp, and transmits a motion control command to the driver after reducing communication delay; the unit module establishes different motion models (dynamic task models) according to different tasks, wherein the motion models comprise an Ackerman geometric steering model and a prediction model;
(3) the driver receives the instruction and controls the wheel part to execute the motor movement;
(4) the encoder detects the rotation angle of the wheel part actuator and the advancing pulse, and the rotation angle and the advancing pulse are processed by the filter and then fed back to the driver;
(5) the inertia measuring unit and the driver respectively feed back the measured attitude information of the unit module and the information of the wheel part actuator to the industrial personal computer;
(6) and (4) processing the feedback information by the industrial personal computer according to the established dynamic task motion model, updating the current state, and repeating the steps (3) - (6) until the next instruction of the upper computer arrives.
The problem to be solved by the Ackerman geometric steering model is steering and self-attitude adjustment;
because the unit module adopts a four-wheel drive four-wheel steering mode without connecting rods among actuators, two Ackermann geometric steering modes are adopted: firstly, a geometric circle center O is fixed on an extension line of a central shaft of the wheeled mobile robot, and four wheel part actuators all execute corner operation and forward movement; secondly, the geometric circle center O is positioned on an extension line of a connecting line of a rear wheel actuator of the wheeled mobile robot, the front wheel actuator performs corner operation and forward movement, and the rear wheel actuator only performs forward movement; in either way, the basic formula for the wheel portion actuator to determine the rotation angle is:
wherein L is the distance from the center of the wheel part actuator to the extension line of the central shaft of the unit module, the intersection point is marked as c, and W is the distance from the geometric center O to the intersection point c; according to different motion selections of the combination, the motion geometry of the unit modules is distinguished by adopting the following two modes;
the motion model of the selection mode I is suitable for motion of the unit modules when the combination body turns, in order to ensure that the relative position of each unit module is not changed when the whole motion is carried out, the circle center O of the geometric turning of each unit module is on the extension line of the central axis of the combination body, and the corresponding rotation angle of the wheel part actuator is calculated by using ij to represent the representation method of the wheel part actuator of the ith row and the jth column according to the following formula:
where r is the radius from which the geometric centre of steering extends, WRIs the width of the unit module, WBIs the distance between two unit modules in the transverse direction, LRIs the length of the unit module, LBIs the distance between the longitudinal directions of the two unit modules; in order to meet the motion requirement, besides the rotation angle of the wheel part actuator, the advancing speed of the wheel part actuator is required to be obtained; the angular speeds of the unit modules are consistent because the unit modules need to ensure that the positions of the unit modules are not changed during integral movement, and the wheel actuators of the unit modules obtain the angular speeds by deriving the angle of the rotation angle
Linear velocity of actuator is mapped to
Will maximize the linear velocity VmaxAs a normalization unit, normalization processing is performed to obtain a given velocity of each actuator
Selecting a motion model in the second mode, wherein the motion model is suitable for adjusting the posture of each unit module when the assembly performs low-speed linear motion; when the combination body performs low-speed linear motion, each unit module obtains a yaw angle error in the motion process through Inertial Measurement Unit (IMU) feedback
At the moment, the geometrical steering is adopted to independently adjust the self posture, so that the unit module moves in the opposite direction of the yaw angle to make up for errors; by adopting the naming method of the mode I, the rotating angle of the actuator of each wheel part is expressed as follows:
the execution speed of each wheel part actuator is selected from the maximum speed of even-numbered behaviors, namely Vmax＝Vij|i＝2kAnd normalizing the odd-numbered wheel part actuators by using the maximum speed, wherein the speed expression rule of the wheel part actuators for executing the corner action is as follows:
the prediction model utilizes the four-wheel-drive characteristic of the wheel actuator to compensate the coordination error between the unit modules by using differential speed; the symbols used will be explained first: p ═ px py pz]TRepresenting the position of the mass center of the unit module, wherein a primary derivative and a secondary derivative of the position respectively represent the speed and the acceleration of the mass center; m is the unit module weight; g is the acceleration of gravity; i is the rotational inertia of the robot; omega ═ phi theta psi]TRepresenting a roll angle, a pitch angle and a yaw angle respectively for the attitude angle of the robot; omega ═ omegax ωyωz]TRepresenting the angular velocity of the unit module; r is a rotation matrix from the machine body to a world coordinate system; f. ofiThe ith wheel part actuator of the current unit module;
firstly, analyzing the dynamic characteristics of the unit module to obtain a simplified dynamic model of the unit module, wherein the simplified dynamic model comprises the following steps:
after a dynamic model is obtained, a state space function is constructed to carry out predictive control on the system state, and state variables are selected
Controlled variable
The output variable is
A state space expression for the system can then be established:
and (3) merging the constant items into the coefficient matrix and discretizing to obtain:
according to the discretization recursion formula, the state of the unit module at n moments is constructed
Xn＝Aqpx[k]+BqpU，
By constructing state X at time nnAnd required state XdesThe minimum weighted norm of the input variable is added with the boundary constraint to convert the minimum weighted norm into a convex quadratic programming problem standard form, namely:
s.t.-μmg≤fix≤μmg
-μmg≤fiy≤μmg
fz≤mg，
using an online quadratic programming solver qpOASES to obtain the required optimal motor force F, and then
And converting the optimal motor force into the optimal output speed of the wheel part actuator.
The invention enhances the synchronism and robustness of the cooperative motion of the multi-unit module, can realize the cooperative motion among a plurality of mobile unit modules, can realize the combination of modules with different configurations aiming at different tasks, and has higher fault tolerance. When the device is used for terrain movement of an unstructured ground, active flexibility of self adjustment of each module is realized on the basis of passive flexibility of a butt joint structure, influence on a system is effectively reduced, and the device has strong external environment movement adaptability.
Drawings
Fig. 1 is a schematic view of a combined configuration of a multi-mobile robot employed in the present invention.
Fig. 2 is a flowchart of the upper computer controlling each unit module.
Fig. 3 is a flowchart of the control method of the present invention.
Fig. 4 is a block diagram illustrating ackermann geometry turning.
FIG. 5 is a schematic diagram of a unit module pose adjustment geometry.
Detailed Description
The combined configuration of the multi-mobile robot adopted in the invention is shown in figure 1, all unit modules with the same configuration or different configurations are connected together through a docking mechanism, each unit module is provided with four wheel actuators which independently turn and independently move, and a triangular or square combined body is formed according to different required tasks. The combinations used are only intended to illustrate the invention and are not intended to limit the scope of the invention.
Each unit module is combined through a docking mechanism, the control system comprises an upper computer, an industrial personal computer, a driver, an inertia measuring unit and an encoder, each unit module is provided with a corresponding industrial personal computer, a corresponding driver, an inertia measuring unit and an encoder, the upper computer is communicated with the industrial personal computers of the unit modules through a network communication protocol, a wheel part actuator is connected with the driver and then connected with the industrial personal computers, the encoders are fixed at driving motors in the actuators, and the inertia measuring units are arranged at mass centers of the unit modules. The encoder is used for detecting the rotation angle of a driving motor in the wheel part actuator, the advancing speed of the current wheel part actuator is obtained through the detected pulse number, the current advancing speed is compared with the preset advancing speed given quantity by the industrial personal computer, the pulse speed required to rotate by the driving motor is obtained, the industrial personal computer sends a processed instruction to the driver, and the driver continuously changes the rotating speed of the driving motor, so that each unit module and other unit modules are in the same stable motion state, and the cooperative motion is completed. The inertia measurement unit sends the measured pose information of the unit modules to the industrial personal computer, a weighted norm is constructed by utilizing the pose information of the unit modules and the established model, the weighted norm is converted into an optimized convex quadratic programming problem through boundary constraint, the self movement error or the influence of external interference is reduced, the change of the pose of the unit modules is realized, and the cooperative motion is carried out in a better way by matching with other unit modules.
The control method of the invention comprises the following steps: establishing a dynamic task model, a state feedback and a geometric method of cooperative motion; when the motion is needed, the current state and pose information of each unit module are fed back through the encoder and the IMU, a discretized combination kinematic model and a weighted norm of an input variable are constructed, the weighted norm is converted into a convex quadratic programming problem through constraint conditions, an optimal solution of the current system input state is solved, a required corner and speed are input to the wheel actuator to achieve cooperative motion on the basis of achieving the local optimal solution.
The control method specifically comprises the following steps:
(1) the upper computer gives instructions and clock timestamps to the industrial personal computer of each unit module
(2) The industrial personal computer receives and processes the instruction, compares the time stamp with a self clock, and issues a motion control instruction to the driver after reducing communication delay.
(3) The driver receives the instruction and controls the wheel part to execute the motor movement.
(4) The encoder detects the rotation angle of the wheel part actuator and the advancing pulse, and the advancing pulse is processed by the filter and then fed back to the driver.
(5) The inertia measuring unit and the driver respectively feed back the measured attitude information of the unit module and the information of the wheel part actuator to the industrial personal computer.
(6) And (4) processing the feedback information by the industrial personal computer according to the established dynamic task motion model, updating the current state, and repeating the steps (3) - (6) until the next instruction of the upper computer arrives.
The upper computer realizes the control flow of each unit module as shown in fig. 2. Fig. 3 shows a flow of the control method of the present invention.
In the step (2) and the step (6), the unit module needs to establish different motion models including an ackerman geometric steering model and a prediction model according to different tasks. The kinematic geometry for establishing ackermann geometric steering is shown in fig. 4 and 5, and the ackermann geometric steering adopted by the unit module aims to solve the problems of steering and self-attitude adjustment, and specific analysis is performed below.
Because the unit module adopts a four-wheel drive four-wheel steering mode without connecting rods among actuators, two Ackermann geometric steering modes can be adopted: firstly, a geometric circle center O is fixed on an extension line of a central shaft of the wheeled mobile robot, and four wheel part actuators all execute corner operation and forward movement; and secondly, the geometric circle center O is positioned on an extension line of a connecting line of a rear wheel actuator of the wheeled mobile robot, the front wheel actuator performs corner operation and forward movement, and the rear wheel actuator only performs forward movement. In either way, the basic formula for the wheel portion actuator to determine the rotation angle is:
wherein L is the distance from the center of the wheel part actuator to the extension line of the central shaft of the unit module, the intersection point is marked as c, and W is the distance from the geometric center O to the intersection point c.
The kinematic geometry of the unit modules is differentiated according to the different kinematic options of the assembly in the following two ways.
The motion model of the selection mode I is generally applicable to the motion of the unit modules when the combination body turns, at this time, in order to ensure that the relative position of each unit module is not changed when the whole motion is performed, the circle center O of the geometric turning of each unit module should be on the extension line of the central axis of the combination body, and by using the expression method that ij represents the ith row and the jth column wheel actuator, the corresponding wheel actuator rotation angle can be calculated by the following formula:
where r is the radius from which the geometric centre of steering extends, WRIs the width of the unit module, WBIs the distance between two unit modules in the transverse direction, LRIs the length of the unit module, LBIs the distance between the longitudinal directions of the two unit modules. In order to meet the motion requirement, the advance speed of the wheel portion actuator is required in addition to the determination of the wheel portion actuator rotation angle. Because each unit module needs to ensure that the position of each unit module is not changed during integral movement, the angular speed of each unit module is consistent, and the wheel part actuator of each unit module can obtain the angular speed by derivation of the angle of the turning angle
The linear velocity of the actuator can be mapped to
Will maximize the linear velocity VmaxAs a normalization unit, normalization processing is performed to obtain a given velocity of each actuator
The motion model of the second selection mode is generally suitable for the posture adjustment of each unit module when the assembly performs low-speed linear motion. When the combination body performs low-speed linear motion, each unit module can obtain the yaw angle error in the motion process through IMU feedback
At the moment, the geometrical steering is adopted to independently adjust the self attitude, so that the unit module moves in the opposite direction of the yaw angle to make up for errors. By adopting the naming method of the mode I, the rotation angle of the actuator of each wheel part can be expressed as follows:
the execution speed of each wheel part actuator is selected from the maximum speed of even-numbered behaviors, namely Vmax＝Vij|i＝2kAnd normalizing the odd-numbered wheel part actuators by using the maximum speed, wherein the speed expression rule of the wheel part actuators for executing the corner action is as follows:
when the assembly executes a high-speed stage of cooperative linear motion, the adopted geometric steering mode has the influence on the cooperation due to the fact that the rotation angle of the geometric steering mode is frequently changed, therefore, a fixed rotation angle motion mode with smaller disturbance needs to be selected, the industrial personal computer needs to establish a prediction model at the moment, and the four-wheel-drive characteristic of the wheel part actuator is utilized to compensate the coordination error between the unit modules by using the differential speed. The symbols used will be explained first: p ═ px py pz]TRepresenting the position of the center of mass of the wheeled robot, wherein a first derivative and a second derivative of the position represent the speed and the acceleration of the center of mass respectively; m is the weight of the wheeled robot; g is the acceleration of gravity; i is the rotational inertia of the robot; omega ═ phiθ ψ]TRepresenting a roll angle, a pitch angle and a yaw angle respectively for the attitude angle of the robot; omega ═ omegax ωy ωz]TRepresenting the angular speed of the wheeled robot; r is a rotation matrix from the machine body to a world coordinate system; f. ofiThe ith wheel part actuator of the current unit module.
Firstly, analyzing the dynamic characteristics of the unit module, and obtaining a simplified dynamic model of the unit module as follows:
after obtaining the dynamic model, a state space function needs to be constructed to carry out predictive control on the system state, and a state variable is selected
Controlled variable
The output variable is
A state space expression for the system can then be established:
the constant terms are combined into a coefficient matrix and discretized to obtain:
according to the discretization recursion formula, the n-moment states of the unit module can be constructed
Xn＝Aqpx[k]+BqpU，
By constructing state X at time nnAnd required state XdesMaximum of input variablesThe small weighted norm, plus the boundary constraint, can be converted into a convex quadratic programming problem standard form, i.e.:
s.t.-μmg≤fix≤μmg
-μmg≤fiy≤μmg
fz≤mg，
the required optimal motor force can be solved by using an online quadratic programming solver qpOASES, and then
The optimal motor force can be converted into the optimal output speed of the wheel actuator.
Claims (4)
1. A multi-mobile robot cooperative motion control system comprises a plurality of unit modules with the same configuration or different configurations, wherein the unit modules are connected together through a docking mechanism, each unit module is provided with four wheel part actuators which independently turn and independently move, and a triangular or square combination is formed according to different required tasks; the method is characterized in that:
the control system comprises an upper computer, industrial personal computers, drivers, inertia measurement units and encoders, wherein each unit module is provided with the corresponding industrial personal computer, driver, inertia measurement unit and encoder;
the encoder is used for detecting the rotation angle of a driving motor in the wheel part actuator, the advancing speed of the current wheel part actuator is obtained through the detected pulse number, the current advancing speed is compared with the preset advancing speed given quantity by the industrial personal computer to obtain the pulse speed required to rotate by the driving motor, the industrial personal computer sends a processed instruction to the driver, and the driver continuously changes the rotating speed of the driving motor, so that each unit module and other unit modules are in the same stable motion state, and the cooperative motion is completed;
the inertia measurement unit sends the measured pose information of the unit modules to the industrial personal computer, a weighted norm is constructed by utilizing the pose information of the unit modules and the established model, the weighted norm is converted into an optimized convex quadratic programming problem through boundary constraint, the self movement error or the influence of external interference is reduced, the change of the pose of the unit modules is realized, and the cooperative motion is carried out by matching with other unit modules more optimally.
2. A control method of a multi-mobile robot cooperative motion control system is characterized by comprising the following steps: the method comprises the following steps: establishing a dynamic task model, a state feedback and a geometric method of cooperative motion; when the motion is needed, the current state and pose information of each unit module are fed back through an encoder and an inertia measurement unit, a discretized kinematic model of the combination and a weighted norm of an input variable are constructed, the weighted norm is converted into a convex quadratic programming problem by utilizing constraint conditions, and a required corner and speed are input to a wheel actuator to realize cooperative motion on the basis of realizing a local optimal solution by solving the optimal solution of the current input state; the method specifically comprises the following steps:
(1) the upper computer sends instructions and clock timestamps to the industrial personal computers of all the unit modules;
(2) the industrial personal computer receives and processes the command, compares the command with a clock of the industrial personal computer by using the timestamp, and transmits a motion control command to the driver after reducing communication delay; the unit module establishes different motion models including an Ackerman geometric steering model and a prediction model according to different tasks;
(3) the driver receives the instruction and controls the wheel part to execute the motor movement;
(4) the encoder detects the rotation angle of the wheel part actuator and the advancing pulse, and the rotation angle and the advancing pulse are processed by the filter and then fed back to the driver;
(5) the inertia measuring unit and the driver respectively feed back the measured attitude information of the unit module and the information of the wheel part actuator to the industrial personal computer;
(6) and (4) processing the feedback information by the industrial personal computer according to the established dynamic task motion model, updating the current state, and repeating the steps (3) - (6) until the next instruction of the upper computer arrives.
3. The control method according to claim 2, wherein: the ackerman geometric steering model solves the problems of steering and self-attitude adjustment;
because the unit module adopts a four-wheel drive four-wheel steering mode without connecting rods among actuators, two Ackermann geometric steering modes are adopted: firstly, a geometric circle center O is fixed on an extension line of a central shaft of the wheeled mobile robot, and four wheel part actuators all execute corner operation and forward movement; secondly, the geometric circle center O is positioned on an extension line of a connecting line of a rear wheel actuator of the wheeled mobile robot, the front wheel actuator performs corner operation and forward movement, and the rear wheel actuator only performs forward movement; in either way, the basic formula for the wheel portion actuator to determine the rotation angle is:
wherein L is the distance from the center of the wheel part actuator to the extension line of the central shaft of the unit module, the intersection point is marked as c, and W is the distance from the geometric center O to the intersection point c; according to different motion selections of the combination, the motion geometry of the unit modules is distinguished by adopting the following two modes;
the motion model of the selection mode I is suitable for motion of the unit modules when the combination body turns, in order to ensure that the relative position of each unit module is not changed when the whole motion is carried out, the circle center O of the geometric turning of each unit module is on the extension line of the central axis of the combination body, and the corresponding rotation angle of the wheel part actuator is calculated by using ij to represent the representation method of the wheel part actuator of the ith row and the jth column according to the following formula:
where r is the radius from which the geometric centre of steering extends, WRIs the width of the unit module, WBIs the distance between two unit modules in the transverse direction, LRIs the length of the unit module, LBIs the distance between the longitudinal directions of the two unit modules; in order to meet the motion requirement, besides the rotation angle of the wheel part actuator, the advancing speed of the wheel part actuator is required to be obtained; the angular speeds of the unit modules are consistent because the unit modules need to ensure that the positions of the unit modules are not changed during integral movement, and the wheel actuators of the unit modules obtain the angular speeds by deriving the angle of the rotation angle
Linear velocity of actuator is mapped to
Will maximize the linear velocity VmaxAs a normalization unit, normalization processing is performed to obtain a given velocity of each actuator
Selecting a motion model in the second mode, wherein the motion model is suitable for adjusting the posture of each unit module when the assembly performs low-speed linear motion; when the assembly performs low-speed linear motion, each unit module obtains the yaw angle error in the motion process through the feedback of the inertial measurement unit
At the moment, the geometrical steering is adopted to independently adjust the self posture, so that the unit module moves in the opposite direction of the yaw angle to make up for errors; by adopting the naming method of the mode I, the rotating angle of the actuator of each wheel part is expressed as follows:
the execution speed of each wheel part actuator is selected from the maximum speed of even-numbered behaviors, namely Vmax＝Vij|i＝2kAnd normalizing the odd-numbered wheel part actuators by using the maximum speed, wherein the speed expression rule of the wheel part actuators for executing the corner action is as follows:
4. the control method according to claim 2, wherein: the prediction model utilizes the four-wheel-drive characteristic of the wheel actuator to compensate the coordination error between the unit modules by using differential speed; the symbols used will be explained first: p ═ px py pz]TRepresenting the position of the mass center of the unit module, wherein a primary derivative and a secondary derivative of the position respectively represent the speed and the acceleration of the mass center; m is the unit module weight; g is the acceleration of gravity; i is the rotational inertia of the robot; omega ═ phi theta psi]TRepresenting a roll angle, a pitch angle and a yaw angle respectively for the attitude angle of the robot; omega ═ omegax ωy ωz]TRepresenting the angular velocity of the unit module; r is a rotation matrix from the machine body to a world coordinate system; f. ofiThe ith wheel part actuator of the current unit module;
firstly, analyzing the dynamic characteristics of the unit module to obtain a simplified dynamic model of the unit module, wherein the simplified dynamic model comprises the following steps:
after a dynamic model is obtained, a state space function is constructed to carry out predictive control on the system state, and state variables are selected
Controlled variable
The output variable is
Establishing a state space expression of the system:
and (3) merging the constant items into the coefficient matrix and discretizing to obtain:
according to the discretization recursion formula, the state of the unit module at n moments is constructed
Xn＝Aqpx[k]+BqpU，
By constructing state X at time nnAnd required state XdesThe minimum weighted norm of the input variable is added with the boundary constraint to convert the minimum weighted norm into a convex quadratic programming problem standard form, namely:
s.t.-μmg≤fix≤μmg
-μmg≤fiy≤μmg
fz≤mg，
using an online quadratic programming solver qpOASES to obtain the required optimal motor force, and then using the optimal motor force
And converting the optimal motor force into the optimal output speed of the wheel part actuator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111297352.4A CN114019915A (en) | 2021-11-04 | 2021-11-04 | Multi-mobile-robot cooperative motion control system and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111297352.4A CN114019915A (en) | 2021-11-04 | 2021-11-04 | Multi-mobile-robot cooperative motion control system and control method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114019915A true CN114019915A (en) | 2022-02-08 |
Family
ID=80060450
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111297352.4A Pending CN114019915A (en) | 2021-11-04 | 2021-11-04 | Multi-mobile-robot cooperative motion control system and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114019915A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116540617A (en) * | 2023-07-06 | 2023-08-04 | 中国科学院空天信息创新研究院 | Unmanned agricultural machinery cooperative work control method introducing weight variable control |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060095169A1 (en) * | 2004-04-15 | 2006-05-04 | Minor Mark A | System and method for controlling modular robots |
| JP2010055415A (en) * | 2008-08-28 | 2010-03-11 | Hitachi Industrial Equipment Systems Co Ltd | Robot system |
| CN108436912A (en) * | 2018-03-27 | 2018-08-24 | 山东大学 | A kind of control system and its control method of reconstruction robot docking mechanism |
| CN110262495A (en) * | 2019-06-26 | 2019-09-20 | 山东大学 | Mobile robot autonomous navigation and pinpoint control system and method can be achieved |
| CN113065259A (en) * | 2021-04-15 | 2021-07-02 | 泉州装备制造研究所 | Coordination method for positions and postures of wallboard assembly and skeleton |
-
2021
- 2021-11-04 CN CN202111297352.4A patent/CN114019915A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20060095169A1 (en) * | 2004-04-15 | 2006-05-04 | Minor Mark A | System and method for controlling modular robots |
| JP2010055415A (en) * | 2008-08-28 | 2010-03-11 | Hitachi Industrial Equipment Systems Co Ltd | Robot system |
| CN108436912A (en) * | 2018-03-27 | 2018-08-24 | 山东大学 | A kind of control system and its control method of reconstruction robot docking mechanism |
| CN110262495A (en) * | 2019-06-26 | 2019-09-20 | 山东大学 | Mobile robot autonomous navigation and pinpoint control system and method can be achieved |
| CN113065259A (en) * | 2021-04-15 | 2021-07-02 | 泉州装备制造研究所 | Coordination method for positions and postures of wallboard assembly and skeleton |
Non-Patent Citations (5)
| Title |
|---|
| LI PING: "Progress of task allocation in multi-robot systems", COMPUTER ENGINEERING AND APPLICATIONS, 1 January 2008 (2008-01-01), pages 201 - 5 * |
| LI, YB (LI, YIBIN): "Immunity-based adaptive genetic algorithm for multi-robot cooperative exploration", LECTURE NOTES IN ARTIFICIAL INTELLIGENCE, 1 January 2007 (2007-01-01), pages 605 - 616 * |
| 王帅；周乐来: "多移动机器人编队领航跟随方法研究进展", 无人系统技术, 31 October 2019 (2019-10-31), pages 1 - 8 * |
| 韩玮: "多机器人集成控制系统的研究", 优秀硕士论文全文库信息科技, 15 September 2021 (2021-09-15), pages 1 - 99 * |
| 顾大强: "多移动机器人协同搬运技术综述", 智能系统学报, 28 February 2019 (2019-02-28), pages 20 - 27 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116540617A (en) * | 2023-07-06 | 2023-08-04 | 中国科学院空天信息创新研究院 | Unmanned agricultural machinery cooperative work control method introducing weight variable control |
| CN116540617B (en) * | 2023-07-06 | 2023-09-08 | 中国科学院空天信息创新研究院 | Unmanned agricultural machinery cooperative work control method introducing weight variable control |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN110989526B (en) | double-AGV cooperative carrying control system and method | |
| CN106125728B (en) | A kind of 4 wheel driven wheeled mobile robot trace tracking and controlling method | |
| Liu et al. | Cooperation control of multiple manipulators with passive joints | |
| US8322468B2 (en) | Robot apparatus and method of controlling the same, and computer program | |
| CN102039589B (en) | Modularized disaster rescue robot | |
| CN107263466B (en) | Base undisturbed control method of space robot based on quadratic programming problem | |
| CN111687821B (en) | Rotary parallel flying mechanical arm system and expected rotation angle calculating method | |
| Zhang et al. | Control of small formations using shape coordinates | |
| CN107505941B (en) | Centralized-distributed control system of four-wheel independent drive and independent steering electric vehicle | |
| CN108508906B (en) | Biped robot bilateral touch teleoperation system and control method in outdoor environment | |
| CN108638068B (en) | Design method of flying robot control system with redundant mechanical arm | |
| CN111459188B (en) | Quaternion-based multi-rotor nonlinear flight control method | |
| Vladareanu et al. | Modeling and hybrid position-force control of walking modular robots | |
| CN201525026U (en) | Modular disaster relief robot | |
| CN114019915A (en) | Multi-mobile-robot cooperative motion control system and control method thereof | |
| CN113821935B (en) | Dynamic model building method and system based on symmetrical constraint | |
| CN115431271A (en) | Anti-interference pointing control method for tail end of aircraft mechanical arm | |
| Sun et al. | A GNN for repetitive motion generation of four-wheel omnidirectional mobile manipulator with nonconvex bound constraints | |
| Yang et al. | Novel decentralised formation control for unmanned vehicles | |
| CN110109353B (en) | Fuzzy self-adaptive sliding-mode control system of counteractive wheel balance bicycle robot | |
| CN117055571A (en) | Mobile robot and cooperative control method and framework thereof | |
| CN111650836A (en) | Control method for dynamically gliding and grabbing object based on operation flying robot | |
| Ma et al. | Energy optimization of an underwater swimming manipulator with rotary thrusters and rolling joints | |
| CN111301552A (en) | Robot leg power system and control method thereof | |
| CN112462753B (en) | Kinematic modeling method for car-snake composite variable structure mobile robot |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |